Process of making azo dyes containing radicals of higher fatty acids.



UNITED STATE-S PATENT oFiiuo NATHAN SULZBERGER, OF BERLIN, GERMANY.

PROCESS OF MAKING AZO DYES CONTAINING RADICALS OF HIGHER FATTY ACIDS.

No. 879,42d.

Specification of Letters Patent.

Patented Feb. 18, 1908.

Application filed March 26. 1907. Serial in. 364.737.

- acids can be converted into the amido-comwhich still contain t pounds by nitration followed byreduction, while the fatty acid radical remains in the compound. These amido compounds can be diazotized and then coupled with aromatic amine or phenols. It has nowbeen shown, that the azo compounds thus obtained,

e fatty acid radical, are distinguished from the other azo colors especially by their fatty nature, which enables them to be utilized with advantage for different Ipurposes in which the azo colors hitherto ave not been suitable or have given poor results.

Any amido fatty acid anilid or naphthalid is suitable for the production of the new azo colors. Substituted amins can also be employed. The fatty acids which can be used are those of fats, such as stearic acid, palmitic acid, oleic acid, erucic acid, brassidic inlaid, ricinoleic acid, oxystearic acid and the The fatty acid anilids are nitrated by the usual methods for example advantageously with a mixture of nitric and sulfuricacids, afterwards reduced with metals and acids, for example zinc or iron and hydrochloric acid, acetic acid or the like, and finally diazotized in the usual way, for example dissolved in g acial acetic or other suitable solvent and treated with nitrous .acid or nitrite. The diazo salts thus obtained are introduced into a solution of phenols, for example, an alkaline solution of phenol, resorcinol, or naphthol or the derivative of a phenol, or naphthol, or into the solution of an amin, advantageously in acetic. acid, (for example naphthylamin, dimethylanilin, phenylenediamin etc.) or the derivative of an amin.- The l possible.

reaction takes place almost instantaneously. The dye-stuff separates out in solid form, or is precipitated by the addition of common salt. It is filtered, washed, and if desired, recrystallized.

Examples.

1. Production of beta naphthoZ-azo-stearicacid-anilid. 10 grams of the anilid of stearic acid are dissolved in 70-80 grams of concentrated sulfuric acid at a moderate temperature (1). To this solution is added about 7 grams of dilute nitric acid of specific gravity 1.17, the temperature being maintained at best between -5060 C. The nitric acid can be added as rapidly as the temperature will allow, and it is best to cool well so that the nitric acid can be run in as quickly as However, should the temperature sink too low, then the anilid readily separates out unchanged, and one runs the risk of some of it escaping nitration. After the addition of all the nitric acid the mixture is pouredstill at 6070 C;into much cold water and vigorously stirred; the yellow nitro compound is filtered off and washed. The p-nitro-stearic-acideanilid thus obtained is quite pure after only one recrystallization from alcohol (with the addition of animal charcoal if necessary), and it is obtained in the. form of small, lemon-yellow, felted needles, which melt between 945 and 955 C. With caustic alkalies, they become intense yellow-red even in the 00 d. This substance (5 grams) is now dissolved in alcohol (about 100 grams), mixed with about 5 grams glacial acetic acid, and iron filings (about 5 grams) are added at about 60 C. during which care must be taken that the metal is introduced in small quantities with constant stirring after each fresh addition. Care should betaken, especially when large quantities are being Worked up, that the reaction does not suddenly become too violent on account of the iron filings being added too quickly to the acid solution.

with water, and the amido cdmpound, colored brownish red by the iron salts which were dissolved in the alcohol is filtered off. The

p The hot solu I 'tion is filtered from the iron, precipitated amido com ound recrystallized from alcohol with the a dition of some animal charcoal is a colorless substance, which melts at 117.5

.in the pure condition, a white crystallinebody, consisting of felted needles, which in contrast to the nitro compound does not What'more than 1 molecule).

give a coloration with caustic potash. It has a fatty feel and after previously sintering at 115116 melts at 118119, forming an almost colorless liquid.

The analysis agrees with the formula Found. Theory. 0 76.84% 77.01% H 11.17% 11.23%

The amido-stearic-anilid is insoluble in ether, petroleum-ether and water; readily soluble in alcohol and chloroform.

The p-amido-stearic-acid-anilid is dissolved in alcohol or the like, or is suspended in some liquid. The liquid in which the .anilid is suspended or dissolved, is acidified with gaseous or aqueous hydrochloric acid at a low temperaturefor instance 0 C. and then treated with gaseous nitrous acid, or a n1- trite, until diazotization is complete. The diazo salt produced can then be brought into solution by gently warming1f necessary with the addition of alcohol, should too much aqueous hydrochloric acid have been taken. (This can be done Without decomposing the diazo compound, because the latter is unusually stable.) One can now pour the strongly acid solution or liquid with precipitate in susension straight into the aqueous, alkaline soution of the naphthol, which must contain so much alkali that the solution reacts alkaline even after the addition of the strongly acid diazo solution. It is better however, to pour the alcoholic solution of the diazo salt into much cold water (if necessary 0n to ice) when the diazo compound separates out as a colorless, solid mass. In the latter case the diazo. salt is filtered off, and is, if necessary dissolved in warm alcohol, or in the solid form as aprecipitate suspended in water, added to the slightly warmed alkaline, preferably very dilute solution of the naphthol (some- The a'zo dyestuff, which separates out almost immediately is of a cinnabar color. It is filtered off well washed and after drying is available for use. The substance can be recrystallized from chloroform for instance 'being soluble in the solvents" for fats. The melting point lies at about 150.

.Various shades are obtained according to the phenol (naphthol) or amin which is used in the coupling with *the diazostearic anilid, for example with Beta naphtholl intense red Beta naphthylaniin- -orange red Resorcinbrown red Dimethylanilin greenish yellow R-salt -raspberry red Alpha naphthol -carmine red Alpha naphthylamin -dark brown Phenolyellow 2. Preparation of dye-staff, starting from the beta naphthylamid 0f palmitic acid. 20

' grams palmitic acid and 13.5 grams naphthylamin are heated inan oil-bath to 260C.

for 1% hours. Towards the close the temperature is raised to 300 C. so that the excess of naphthylamin to a great extent is sublimed off. The mass is often shaken during the heating. The raw product, while yet fluid, is poured into 200 grams glacial acetic acid and into the clear solution thus obtained, warmed to C., are poured all atvolume of glacial acetic acid; and then treated at 60 0., with small uantities of iron filings, well stirred into t e mixture, until the yellow nitro compound is completely reduced and a small sample, filtered off, gives a pure white precipitate on the addition of water and hydrochloric acid.

After standing a short time, with frequent stirring, the still warm solution is filtered from the iron, and the filtrate, when cold, poured into cold water. The almost colorless amido compound is filtered off and the iron salts washed out as completely as possible. The pure amido compound forms a white, colorless crystalline powder, having a fatty feel. The body is insoluble even in boiling water, and does not melt under these conditions. It is readily soluble in alcohol, benzene and chloroform, and diflicultly in ether and petroleum-ether. The amidobody is dissolved in alcohol, strongly acidified with concentrated hydrochloric. acid, and the partly dissolved, partly suspended body diazotized at 0 with gaseous, nitrous acid. After complete diazotization cold is filtered offand washed. The product,

finely suspended in Water. can now be used for coupling.

The following colors were obtained, with Y Dimethylanilin brownish-yellow The dyestuifs have a pronounced fatty character, give for example grease-spots and prevent the wetting of the dyed'material. They float on water like the fats.

3. Preparation of dye-stafls from oleic acid. 50 grams of oleic acid are heated in a reflux apparatus with 40 grams of anilin for 9 hours, the oil-bath being maintained at 240260 C. Finally the excess of anilin is distilled ofl at about 300 C. The oleic-acidanilid is cautiously dissolved in about 900 grams concentrated sulfuric acid, to which is slowly added at 5 0., 50 grams nitric acid (s'p. gr. 1.17) with constant stirring. On carefully pouring into ice-water, the yellow nitro compound separates out. This is fil- 't'ered off, washed and dissolved in alcohol. The solution is mixed with aqueous concentrated hydrochloric acid, and treated gradually at 60 C. with small portions of iron powder with constant stirring until reductlon is complete, and a small sample of "the solution gives a pure white flocky precipitate i alcohol containing acid, The

' under amido-stearic-anilid.

of the amido compound on the addition of water. The amido compound is much more soluble than the nitro-body, especially in excess of iron is filtered off, and the filtered solution poured, when cold, into much cold water. The body separates outin colorless flocks, which are filtered off and washed. The diazotization is carried out as described The couplings gave the following colorations:

. PhenoL- orange a naphthol Bordeaux red [5 naphthol intense red Naphthylamin (in strong acetic acid) violet fl naphthylamin orange Dimethylanilin ireddish-yellow R-salt. bright red Resorcindark brown 4. Preparation of dye stafis starting from paZmitic-acid-anilid.50 grams of palmitic acid are boiled for 6-7 hours at 240260 C. with .40 grams of anilin. The excess of anilin is distilled 0H, the residue dissolved in 800900 grains concentrated sulfuric acid and nitrated at 40 with 50 grams nitric acid (sp. gr. 1-17). The roduct is poured into water and the precipitate-filtered off and washed. The nitro compound, dissolved in alcohol, is now reduced at '70? With alcoholic hydrochloric acid and iron or dissolved in fats etc.

filtered from a little oily by-product which often forms, and then poured into cold water. The di'azo compound thus obtained is finely suspended in water and finally coupled with the phenols and amins. The following colorations were obtained:

Alpha naphthol carmine red Beta naphtholintense red Alpha naphthylaminbrownish-red Beta naphthylamin yellowish-brown Dimethylanilin- -1 yellow Resorcin dark-brown Instead of the pure acids and amins etc.

mixtures of the different fatty acids and amins can be used. l The compounds thus obtained are char acterized by being on the one hand real dyestuffs, but on the other hand they have also a fatty nature, in consequence of which they behave like fats they can therefore be mixed, and dissolved in the latter, and also in the usual solvents for fats such as wax, fats, paraflins etc. These bodies can consequently be employed in all those cases, where a color, soluble in fats, is desired. These colors for example therefore can be used as cosmetic paints, either in substance In this particular application, these bodies in consequence of their fatty properties possess the particular advantage of readily forming emulsions with soaps, and the like, and are thus easily removed again from' the skin. Again they can likewise be used as pigments and artists colors, dissolved for example in turpentine or some other suitable vehicle. Formerly where such properties were desired, only a limited number of dyes and colors could be used, and it was necessary to employ, in most cases, mere mechanical mixtures of colors with waxes and other vehicles; a

method which possessed the disadvantage that the mixing was'often imperfect, and the mixture was of a more or less unstable nature. As moreover these new compounds generally melt withoutdecomposition, the higher melting ones can be melted and cast into sticks, in which form they can also be conveniently brought on to the market. These new bodies, in addition, are very stable towards acids and alkalies and can consequently be brought into contact with acids and alkalies without fearing chemical changes; a property which would enable these dyestuffs to be used in the manufacture of colored soaps and the like. As these bodies are also without smell and taste they can also be used with advantage in all such cases, Where these properties are valuable and desirable. Another advantage of these bodies is that they do not decompose on keeping, or become rancid, although they are completely fatty in character. In consequence of the high melting points of a large number of these dyestuffs, they do not depress the melting point of stearin, tallow, etc.- and hence these compounds are suitable for coloring candles. Wool, silk and cotton can also be dyed, best with solutions of these fatty colors for instance in alcohol, and are then more or less water-proof in consequence of the fatty nature of these dyestufi's.

What I claim as my invention and desire by Letters Patent is: I

A process for the production of azo dyestuffs, containing the radical of a fatty acid occurring in fats, consisting in coupling the diazo compounds of'the amido-fatty acidarylids with amins and phenols, substantially as and for the purpose set forth.

12th day of March, 1907. NATHAN SULZBERGER.

Witnesses:

HAROLD BARON,

FRANoIs WILLIAM KAY. 

